Atmospheric radars involve large investments and it is necessary that an in-built self-calibration facility is introduced for routine check of the 'health' of the system. In India, an MST radar is currently being built at Gadanki near Tirupati (13.456-degrees-N, 79.176-degrees-E) for studying the dynamics of upper atmosphere. During the first phase the radar is operated in ST mode where it is to probe the atmosphere up to heights of 25 km for vertical beam and 15 km for off-vertical beam. A method similar to phase-switched interferometry has been devised for calibration of ST radar and some results of the experimentations carried out on the radar are presented. Using this method the beam pointing accuracy, the beam width and gain of the receiving antenna can be checked routinely.